The sky in the city of SP is affected by smoke from the fires this Saturday; air quality drops and there may be dark rain | Saint Paul

Air quality was compromised in São Paulo, according to the São Paulo State Environmental Company (Cetesb). The air condition was moderate to very bad at all Cetesb measuring stations in the capital.

The phenomenon of dark rain, which occurs when rain clouds meet soot from burning, can occur between the night of this Saturday and this Sunday (20). The collected water can appear attenuated due to the accumulation of contaminants.

In addition to the dark mist in the sky, the inhabitants of the capital also reported the smell of smoke.

“And the smell? Terrible. Sulfur, something like that. A very complicated smell,” said José heleno da Silva, maintenance technician.

“It’s already bad to breathe with a mask, with bad air it gets worse,” complains Deivid Sebastião, assistant.

A change in the direction of the wind also reduces the concentration of pollutants and allows, as of Monday (21), the smoke to leave the state of São Paulo. The rain that can occur in the city at the end of this Saturday night should be isolated, occurring only in some regions, but it can have lightning and strong winds in some points.

The cold front should also affect the thermometers: between Sunday and Tuesday temperatures should not reach 20ºC in the capital.

According to Climatempo meteorologist Daniela Freitas, the arrival of a cold front should bring rain and, with it, the possibility of pollution dissipating.

“As we must have the arrival of a new cold front here in the metropolitan area at the end of the day, there is the possibility that this rain associated with that front washes the atmosphere and thus we can have rain again with soot particles, collected from this plume. of soot, of that smoke, of the fires that come from the Midwest here in the capital, ”said Freitas.

Satellite images show that wind currents bring smoke from burning in the Pantanal in the Midwest, Bolivia and Paraguay. On the map it is possible to differentiate smoke from rain clouds due to the tone. The smoke is light gray, while the white part is the clouds that come with the cold front. In São Paulo, they mix.

And since the forecast is for rain, the researchers are already preparing for a new collection. The water will be taken to research laboratories and experts are already hoping to find toxic substances that are bad for health.

“The material from the black rain last year, we did chemical analysis and it has a series of chemicals that are derived from burning mainly plant material. Some of these substances, derived from burning, can be toxic. If we expire the smallest particles, yes, they can cause a problem, especially at this time that we have the Covid-19 pandemic in which the lung is our most sensitive part. This mainly affects people who have asthma or rhinitis, ”explains Marcos Buckeridge. , director of the Institute of Biosciences of USP.

This Friday, the capital of São Paulo had isolated rains, but they were not enough for the dispersion of the polluting particles. Black rain should occur until Sunday (20) when the city can have more intense rains due to heat with the approach of a cold front.

This year, fire outbreaks in SP more than doubled, compared to 2019. The increase occurred especially in the months of August and September.

On August 19, 2019, the phenomenon of black rain occurred in the city of São Paulo due to the fires that occurred in the Amazon. Technical analyzes from two universities showed that dark-colored rainwater collected by residents of the capital contained particles from the burning. On social media, residents of Greater São Paulo posted images of dark rainwater.

The test carried out by the Institute of Chemistry of the University of São Paulo (USP) identified the presence of retention, a substance from biomass burning and considered a marker of burning, in the rainwater collected on Monday.

The examination carried out by the Municipal University of São Caetano (USCS) showed that the concentration of particulate matter, that is, soot, was seven times higher than that registered in normal rainwater.

While USP researchers looked at retention identification, which is a fire marker, the USCS analysis found 7 times the normal amount of soot and the presence of sulfides 10 times the average. The substance comes from the burning of fossil fuels and fires.